Process for testing catalysts using mass spectroscopy

ABSTRACT

Methods for evaluating catalysts, in which a multicell holder, e.g., a honeycomb or plate, or a collection of individual support particles, is treated with solutions/suspensions of catalyst ingredients to produce cells, spots or pellets holding each of a variety of combinations of the ingredients, is dried, calcined or treated as necessary to stabilize the ingredients in the cells, spots or pellets, then is contacted with a potentially reactive feed stream or batch, e.g., biochemical, gas oil, hydrogen plus oxygen, propylene plus oxygen, CCl 2 F 2  and hydrogen, etc. The reaction occurring in each cell can be measured, e.g., by infrared thermography, spectroscopic detection of products or residual reactants, or by sampling, e.g., multistreaming through low volume tubing, from the vicinity of each combination, followed by analysis, e.g., spectral analysis, chromatography, etc., or by observing temperature change in the vicinity of the catalyst, e.g., by thermographic techniques, to determine the relative efficacy of the catalysts in each combination. Robotic techniques can be employed in producing the cells, spots, pellets, etc.

This application is a divisional of co-pending U.S. Ser. No. 09/499,956filed Feb. 8, 2000, and issued as U.S. Pat. No. 6,333,196, which is adivisional of U.S. Ser. No. 08/664,836 filed Jun. 17, 1996 and issued asU.S. Pat. No. 6,063,633, which itself claims the benefit of U.S. Ser.No. 60/012,457 filed Feb. 28, 1996.

BACKGROUND OF THE INVENTION

I. Field of the Invention

The present invention relates to the general field of catalyst testing,generally classified in U. S. Patent Class 502 or 252.

II. Description of the Prior Art

Prior Art will include C & E News, Jan. 8, 1996, p.30 which teachesreactive plastics, and the many catalyst testing devices and processesknown to the petroleum refining art. F. M. Menger, A. V. Fliseev, and V.A. Migulin, “Phosphatase catalysts developed via combinatorial organicchemistry”, J. Org. Chem. Vol. 60, pp 6666-6667, 1995. Xiang, 268Science 1738 and Bricenol, 270 Science 273, both on combinatoriallibraries of solidstate compounds; Sullivan, Today's Chem. At Work 14 oncombinatorial technology; Nessler 59 J. Org. Chem. 4723 on tagging ofcombinatorial libraries; Baldwin, 117 J. Amer. Chem. Soc. 5588 oncombinatorial libraries.

Problems Presented by Prior Art

Catalyst testing is conventionally accomplished in bench scale or largerpilot plants in which the feed is contacted with a catalyst underreaction conditions, generally with effluent products being sampled,often with samples being analyzed and results subjected to dataresolution techniques. Such procedures can take a day or more for asingle run on a single catalyst. While such techniques will have valuein fine-tuning the optimum matrices, pellet shape, etc., the presentinvention permits the scanning of dozens of catalysts in a singleset-up, often in less time than required for a single catalyst to beevaluated by conventional methods. Further, when practiced in itspreferred robotic embodiments, the invention can sharply reduce thelabor costs per catalyst screened.

SUMMARY OF THE INVENTION

General Statement of the Invention

According to the invention, a multisample holder (support) e.g. ahoneycomb or plate, or a collection of individual support particles, istreated with solutions/suspensions of catalyst ingredients to fill wellsin plates, or to produce cells, spots or pellets, holding each of avariety of combinations of the ingredients, is dried, calcined orotherwise treated as necessary to stabilize the ingredients in thecells, spots or pellets, then is contacted with a potentially reactivefeed stream or batch e.g., to catalyze biochemical reactions catalyzedby proteins, cells, enzymes; gas oil, hydrogen plus oxygen, ethylene orother polymerizable monomer, propylene plus oxygen, or CC12F2 andhydrogen. The reaction occurring in each cell is measured, e.g. byinfrared thermography, spectroscopic, electrochemical, photometric,thermal conductivity or other method of detection of products orresidual reactants, or by sampling, e.g. by multistreaming through lowvolume tubing, from the vicinity of each combination, followed byanalysis e.g. spectral analysis, chromatography etc, or by observingtemperature change in the vicinity of the catalyst e.g. by thermographictechniques, to determine the relative efficacy of the catalysts in eachcombination. Robotic techniques can be employed in producing the cells,spots. pellets) etc. Each of these parameters is discussed below:

Catalysts: Biotechnology catalysts include proteins, cells, enzymes,etc. Chemical conversion catalysts include most of the elements of thePeriodic Table which are solid at the reaction conditions Hydrocarbonconversion catalysts include Bi, Sn, Sb, Ti, Zr, Pt, the rare earths,and many possible candidates whose potential has not yet been recognizedfor the specific reaction. Many synergistic combinations will be useful.Supported metals and metal complexes are preferred. The chemicalcatalysts can be added to the substrate (support) as elements, asorganic or inorganic compounds which decompose under the temperature ofthe stabilizing step, depositing the element or its oxide onto thesubstrate, or as stable compounds.

Supports: Supports can be inert clays, zeolites, ceramics, carbon,plastics, e.g. reactive plastics, stable, nonreactive metals, orcombinations of the foregoing. Their shape can be porous honeycombpenetrated by channels, particles (pellets), or plates onto whichpatches (spots) of catalyst candidates are deposited or wells in plates.Conventional catalyst matrix materials such as zeolites e.g. zeoliteUSY, kaolin, alumina, etc. are particularly preferred as they cansimulate commercial catalysts.

Preparation: The catalyst candidate precursors can be deposited onto thesupports by any convenient technique, preferably by pipette or absorbingstamp (like a rubber stamp), or silk screen. In preferred embodiments,the deposition process will be under robotic control, similar to thatused to load multicell plates in biochemical assays. Many of the spotsof catalyst will be built up by several separate depositions e.g. achannel penetrating a honeycomb can be plugged at one third of itslength and the channel filled with a catalyst solution in its upperthird, then the plug can be moved to the two-thirds point in the channeland a second catalyst pipetted in, then the plug can be removed and athird catalyst solution added, resulting in a channel in which reactantscontact three catalysts successively as they flow through the channel.Catalyst can also be added by ion exchange, solid deposition,impregnation, or combination of these. The techniques of combinatorialchemical or biological preparation can preferably be utilized to preparean array of candidate catalysts with the invention. Coprecipitates oftwo or more catalysts can be slurried, applied to the support, thenactivated as necessary. Catalysts can be silk screened onto a supportplate or inside of a support conduit, and successive screenings can beused to add different catalyst combinations to different spots.

Stabilizing Step: Once the catalysts are in place on the support, anysuitable technique known to the art can be used to stabilize, and/oractivate the particular catalysts chosen, so they will remain in placeduring the reaction step. Calcining, steaming, melting, drying,precipitation and reaction in place will be particularly preferred.

Reactants: The Invention has utility with any reaction which can beenhanced by the presence of a catalyst, including biological reactionsand inorganic and organic chemical reactions. Chemical reactions includepolymerization reactions, halogenation, oxidation, hydrolysis,esterification, reduction and any other conventional reaction which canbenefit from a catalyst. Hydrocarbon conversion reactions, as used inpetroleum refining are an important use of the invention and includereforming, fluid catalytic cracking, hydrogenation, hydrocracking,hydrotreating, hydrodesuifuiwzing, alkylation and gasoline sweetening.

Sensors: The sensors used to detect catalytic activity in the candidatecatalysts are not narrowly critical but will preferably be as simple aspractical. Chromatographs, temperature sensors, and spectrometers willbe particularly preferred, especially those adapted to measuretemperature and/or products near each specific catalyst spot e.g. bymultistreaming, multitasking, sampling, fiber optics, or lasertechniques. Thermnography, as by an infrared camera recording thetemperature at a number of catalyst sites simultaneously, isparticularly preferred. Other suitable sensors include NMR, NIR, TNIR,electrochemical, fluorescence detectors, Raman, flame ionization,thermal conductivity, mass, viscosity and stimulated electron or X-rayemission Sensors can detect products in a gas or liquid stream or on thesurface of the support.

Endothermic reactions exhibit reduced temperature at best catalysts.Some sensors employ an added detection reagent, e.g. ozone to impartchemiluminesce.

Taggants: Optionally taggants (labels) can be added to identifyparticular catalysts, particularly where particles are employed assupports for the catalysts. These taggants can be conventional asdiscussed in the literature. Taggants can be chemicals which are bystable at reaction conditions or can be radioactive with distinctiveemissions. The techniques of combinatorial chemistry will be applicablewith taggants as well as with catalysts chosen to suit the particularreaction to be enhanced by the catalyst.

Batch or Continuous: While the invention will be preferred on a flowbasis, with reactants flowing by the catalyst spots under reactionconditions, batch testing e.g. in a stirred autoclave or agitatedcontainers, can be employed, particularly in biological reactions.

Temperatures, pressures, space velocities and other reaction

conditions: These will be determined by the reactants and reaction.Elevated pressures can be provided as reaction conditions by encasingthe support in a reaction chamber with a sapphire or similar window forobservation by the sensing means, or with pressure-tight leads extendingthrough the reactor walls.

II. Utility of the Invention

The present invention is useful in the testing of catalysts forbiotechnology, for promotion of gas phase and liquid phase reactions;under batch or, preferably, continuous flowstream conditions; atelevated, reduced or atmospheric pressure; and saves both elapsed timeand labor in screening for improved catalysts to promote a desiredreaction.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a preferred honeycomb support with arobotic pipetting device depositing different combinations of catalystingredients into each of the channels running through the honeycomb,which is thereafter calcined to stabilize the catalysts in each channel.

FIG. 2 is shows schematically the honeycomb of FIG. 1 being contacted byreactants flowing through the channels.

FIGS. 3a and 3 b are alternative schematic diagrams of one channel ofthe honeycomb of FIG. 2 with a detector sensing the products exiting thechannel by measuring absorption in a laser beam directed through theproducts or the channel.

FIG. 4a shows a channel plugged at its midpoint prior to receiving asolution of catalyst and FIG. 4b shows the plug moved to the end of thechannel, so as to form a channel having one catalyst in one half itslength and another catalyst in its other half.

FIG. 5 shows schematically a sheet of support onto which 15 spots ofdifferent catalyst combinations have been deposited, as discussed inexample 1.

FIG. 6a shows an array of particles (pellets) of support in place in areactor after having been ion exchanged with different catalystcombinations on different pellets (denoted schematically by differentmarkings on the pellets in the Figure). FIG. 6b shows a packed reactorwhich is less preferred because upstream pellets see fresh feed, whiledownstream pellets see partially reacted feed.

FIG. 7 shows schematically the use of various detectors on the candidatecatalyst array of FIG. 5.

FIG. 8 shows schematically the use of thermal, electrochemical, flameionization, etc. detectors on the candidate catalyst array of FIG. 5.

FIG. 9 shows schematically the use of low volume sampling tubes withvarious analyzers on the candidate catalyst array of FIG. 5.

FIG. 10 shows schematically the use of a candidate catalyst arraydeposited on the interior of a monolith.

FIG. 11 shows schematically the use of a flow reactor with sapphirewindow open to various detectors on the candidate catalyst array of FIG.5, and shows optional pressure tight electrical leads 13 for leading toa detector.

FIG. 12 shows schematically the apparatus of Example 13.

FIG. 13 shows schematically the apparatus of Examples 14 and 16.

DESCRIPTION OF THE PREFERRED EMBODIMENTS EXAMPLE 1

Referring to FIG. 1, a sheet of alpha alumina 10 is wash-coated withparticles of porous gamma-alumina by standard methods. Solutions ofoxalate salts of 12 different transition metal elements are prepared inthe wells of a 24 well microtiter dish made of polystyrene. A BeckmanBiomek 2000 robotic automated liquid handling system is used to preparedilutions and mixtures from the original stocks, again in the wells ofmicrotiter style plates. The robot is used to deposit 20 microtiteraliquots of each of the resulting solutions at defined positions (spots)12 on the surface of the alumina support 10, which is then dried,calcined and inserted into a reactor capable of temperature control attemperatures from 100 to 350 degrees centigrade. After reduction, apotentially reactive mixture of oxygen and hydrogen is fed to thereactor. An Agema infra-red sensitive camera 14 is used to observe thealumina support through infra-red-transparent sapphire windows 16 shownin FIG. 11, via a polished metal mirror. The camera is set so that thelower end of its dynamic range corresponds to a temperature of about 40degrees C. below the feed temperature and the maximum signal isassociated with a temperature about 200 degrees higher. Compositionscatalyzing the reaction are revealed by the localized temperatureincreases (decreases for endothermic reactions) around spots 12 of thatcomposition, as shown on photograph 18 in FIG. 5.

EXAMPLE 1a

Catalysts are alternatively identified by conducting the reaction in thepresence of strong ultraviolet and/or visible light illumination withinfrared thermography being conducted immediately after the illuminationis turned off, or through the use of a short pass filter on theillumination source to eliminate contaminating infra-red radiation.

EXAMPLE 2

Referring to FIG. 2, a porous alumina monolith 20 (Corning) havingsquare or circular cross-section channels extending in a regular arraythrough its entire thickness is treated in each channel with a solutionof catalyst precursors of differing compositions, with each compositionbeing segregated in its own channel. After drying, calcination, etc.,the activated monolith is placed in contact with a flowing potentiallyreactive mixture at an elevated temperature, and observed in theinfra-red using an Agema model camera. The enthalpy of reaction produceslocalized temperature differences in the vicinity of compositionsexhibiting catalytic activity and these are observed as temperaturevariations near the exits of the channels.

EXAMPLE 3

Referring to FIG. 3, a porous ceramic monolith 20 of the type describedin Example 2, bearing various catalyst compositions in its channels isinstalled in a reactor (not shown) in such a way that the entire lengthof each channel can be observed through sapphire windows at the ends ofthe reactor. A broad-spectrum thermal infrared source is installed atone end of the reactor, giving an areal infrared energy flux density. AnAgema IR-sensitive camera is positioned in such a way as to observe theinfra-red source directly through a significant fraction of the pores.An interferometric or other is filter is installed on one side of thereactor between the camera and the infra-red source such that the lightreaching the camera from the source is substantially limited towavelengths between 4 and 4.5 microns. Observation of absorbency at thiswavelength range is used to compare candidate catalyst compositions onthe basis of their production of carbon dioxide, an undesired sideproduct of the intended reaction. Catalyst compositions chosen for lowcarbon dioxide formation (in combination with high overall conversionactivity as measured by infra-red absorbance of the desired product orby infrared thermography) are found to have high selectivity for thedesired product over the carbon dioxide side product.

EXAMPLE 4

A collection of catalyst precursor compositions is produced by automatedliquid handling device, and a catalyst support particle is contactedwith each composition. After further treatment to stabilize and activatethe catalyst precursors, catalyst pellets are arrayed on a surface,exposed to a potentially reactive environment and their activitydetermined by infrared thermography.

EXAMPLE 5

Solutions of combinations of catalyst precursors are prepared in avariety of separate vessels. Each composition also contains a smallquantity of a labeling material (e.g., stable isotopes of the elementcarbon or sulfur in varying ratios). Catalyst support particles arecontacted with catalyst precursor preparations, and activated. Pelletsare then contacted one at a time with a potentially reactive mixture(for example, by elutriation into an enclosed volume) and their activitymeasured (by thermography, by spectroscopic measurement of products, orsampling of the surrounding vapor or liquid phase). Particles showingactivity are collected and individually analyzed for their content ofthe labeling material so as to determine the composition giving thedesired catalytic activity.

EXAMPLE 6

Example 2 is repeated except that only a portion of the pore length iscoated with a catalyst candidate so as to allow for observation ofunmodified monolith pore wall as a control reference standard foroptical uniformity.

EXAMPLE 7

The emissivity of the support monolith pores of the support 20 ofExample 2 is mapped at a wavelength of interest by holding the monolithat the intended experimental temperature in reactants. Digitally storedmaps of the emissivity are used to normalize the infra-red energy fluxmeasured under experimental conditions, to improve the accuracy withwhich local temperatures can be estimated.

EXAMPLE 8

A surface of high, substantially uniform emissivity is located at theend of the monolith of Example 2, away from the camera, in closeradiative heat transfer/contact with the monolith channel material. Thetemperature of the portion of the surface closest to the open end ofeach channel is observed. In this case, it is necessary that gas beadmitted into the channels past the uniform radiative surface, either bymeans of pores or by means of a small offset between the radiativesurface and the monolith.

EXAMPLE 9

Alternatively, spots of catalysts can be deposited on the inner surfaceof a reactor e.g. a tube formed of the support material as shown in FIG.10, and temperature of the corresponding spots on the outside of thereactor can be measured to determine by conduction whether therespective catalyst has increased or decreased in temperature under thereaction.

EXAMPLE 10

The process of Example 1 is repeated except that the reactants are inthe liquid phase and a liquid phase assay is used (FIG. 12) to detectthe activity of individual catalyst candidates.

EXAMPLE 11

The experiment of Example 4 is repeated except that the metal loading isdirectly measured by dissolving the pellet and directly analyzing themetal loading.

EXAMPLE 12

A sheet of alpha alumina 5 in FIG. 12, is wash coated with particles ofporous gamma-alumina by standard methods. Solutions of oxalate salts of12 different transition metal elements are prepared in the wells of a 24well micro titer dish made of polystyrene. A Beckman Biomek 2000automated liquid handling system is used to prepare dilutions andmixtures of the original stocks, again in the wells of microtiter styleplates. The Biomek robot 6 is used to deposit 40 microliter aliquots ofeach of the resulting solutions at defined positions on the surface ofthe alumina support, which is then dried, calcined and inserted into areactor (as shown in FIG. 11) controlled at a temperature of 200 degreescentigrade. A gaseous mixture of hydrogen (97.5%) and oxygen (2.5%) isfed at a temperature of 200 degrees centigrade. Using the apparatus ofFIG. 11, an infra-red sensitive camera 14 is used to observe the aluminasupport through infra-red-transparent sapphire windows 16. The camera isset so that its lower range corresponds to the feed temperature and themaximum signal is associated with a temperature degrees 20 degreeshigher. Compositions catalyzing the reaction are revealed by thelocalized temperature increases around spots of that composition.

EXAMPLE 13

A porous alumina monolith 140 in FIG. 12, having square pores extendingin a regular array through its entire thickness at a density of 25 persquare inch is washcoated with alumina particles. The channels are thenpartially filled with solutions of differing compositions, eachcontaining one or more metal oxalate or nitrate salts, with eachcomposition being segregated in its own channel or set of channels.After drying and activation in the presence of hydrogen gas, theactivated monolith is placed into a sapphire-window-equipped reactor 150in which it can be observed in the infrared using an IR-sensitive camera145. The camera is positioned in such a way as to observe the walls ofthe support. The relative emissivity of the support at each pixel isdetermined by imaging the monolith in the IR while holding the reactorand monolith at each of several constant temperatures while flowingnitrogen gas 153 through the reactor.

The reactor is then fed with a gas mixture of 2.5 mole % oxygen inhydrogen 154. The reactor and feed temperatures are originally set to 40degrees centigrade, and are gradually increased While thecatalyst-bearing monolith is repeatedly imaged in the IR. Thetemperature in each cell may be judged by observing the cell at aposition adjacent to the end of the catalyst-precursor-coated section ofthe channel, or by normalizing the observed IR energy emission by theemissivity calculated from the images taken under nonreactiveconditions. The compositions in the cells showing the earliesttemperature increase above the reactor temperature are useful ashydrogen oxidation catalysts.

EXAMPLE 14

A porous alumina monolith 140 in FIG. 13 having square channels in aregular array extending through its entire 10 centimeter thickness at adensity of 25 per square inch is washcoated with alumina particles. Thechannels are then partially filled with solutions of differingcompositions, each containing one or more metal salts and in some casesalso candidate modifiers such as barium, cesium or potassium compounds,each composition being segregated in its own channel or set of channels.

After drying and reduction in the presence of hydrogen gas, theactivated monolith is placed into a reactor in which it can be observedthrough a sapphire window 172 using an IR-sensitive camera 170.

This first window 172 is positioned 0.5 centimeter from the surface ofthe monolith. The camera 170 is positioned in such a way as to lookthrough the window 172, through the channels of the support and througha second sapphire window 174 toward a source of IR radiation 164.

The reactor 168 is then fed with methane gas, mixed with oxygen andargon, in such a way that the gas 165 flows through the channels of themonolith toward the camera. An optical filter 162 which selectivelypasses IR radiation at 4.3 microns, a wavelength which is stronglyabsorbed by carbon dioxide, is inserted between the IR source and thecamera. The effective concentration of carbon dioxide in each channel isinferred from the IR intensity at 4.3 microns seen in that channel. Thereading at 4.3 microns for each pixel is divided by the reading takenthrough a filter selective for an IR wavelength which is near 4.3microns, but which is not absorbed strongly by carbon dioxide, methaneor water, to compensate for potential optical artifacts.

Compositions giving high concentrations of carbon dioxide after longexposures to operating conditions are useful in catalytic oxidation ofmethane.

EXAMPLE 15

Solutions of combinations of catalyst precursors are prepared in avariety of separate vessels. Each composition also contains a smallquantity of a labeling material (e.g., stable isotopes of the elementsulfur in varying ratios unique to each composition). Catalyst supportparticles are contacted with the preparations of catalyst precursorcompositions, and activated. Pellets are then contacted one at a timewith a potentially reactive mixture (for example, by elutriation into anenclosed volume) and their activity measured (by thermography, byspectroscopic measurement of products, or sampling of the surroundingvapor or liquid phase). Particles showing activity are collected andindividually analyzed for their content of the labeling material so asto determine the composition giving the desired catalytic activity.

EXAMPLE 16

A Teflon block monolith 140 in FIG. 13, having square channels in aregular array extending through its entire thickness at a density of 9per square inch is prepared in such a way that a shallow well exists atthe bottom of each channel. Each well is charged with a differentpolymer preparation bearing sulfonic acid groups on its surface, and aporous retaining mesh installed to keep the polymer samples in place.

The catalyst-charged monolith is placed into a reactor in which it canbe observed through a window 172, positioned 0.5 centimeter from thesurface of the block. A camera 170 is positioned in such a way as tolook via through the sapphire window, through the channels of thesupport and through a second window 174, toward a source of polarizedlight 164. A polarizer 162 is installed between the block and thecamera.

A sucrose solution 166 is fed to the reactor in such a way as to flowthrough the channels of the block. The angle of rotation of polarizedlight in passing through the liquid in each channel is measured byrotating the polarizer to various angles, and observing the variation inbrightness of the light passing through each channel. The candidatecatalysts found in channels giving the greatest change in the angle ofrotation are useful as catalysts of sucrose hydrolysis.

EXAMPLE 17

Catalysts for photooxidation of hexane are identified by conducting thereaction in the apparatus of Example 16 in the presence of strongultraviolet and/or visible light illumination, with infra-redthermography being conducted immediately after the illumination isturned off, or through the use of a short pass filter on theillumination source to eliminate contaminating infrared radiation.

EXAMPLE 18

Samples of cyanogen bromide-activated cross linked agarose beads areexposed to solutions of alcohol oxidase at varied pHs, saltconcentrations, and enzyme concentrations. After coupling of the enzyme,residual active groups are quenched with ethanolamine, the beads arewashed, and each sample placed in a separate well of a multiwell plate.The plate is exposed to a flowing air stream containing ethanol vaporand observed with an Amber infrared-sensitive camera.

The samples showing the greatest temperature increase are selected ashighly active immobilized alcohol oxidase catalysts.

EXAMPLE 19

Samples of cyanogen bromide activated cross linked agarose beads areexposed to solutions of anti-alcohol oxidase antibodies at varied pHs,salt concentrations, and antibody concentrations. After coupling of theenzyme, residual active groups are quenched with ethanolamine. The beadsare washed, exposed to a solution of alcohol oxidase) washed again, andeach sample placed in a separate well of a multlwell plate. The plate isexposed to a flowing air stream containing ethanol vapor and observedwith an Amber infrared-sensitive camera.

The samples showing the greatest temperature increase are selected ashighly active immobilized alcohol oxidase catalysts.

EXAMPLE 20

A ceramic monolith having channels arranged in perpendicular row/columnformat passing through its entire thickness is washcoated with porousalumina particles and all the channels in each column are treated withthe same catalyst precursors, which are activated. Apotentially-reactive stream is flowed through the channels of themonolith, and a multiwavelength beam of radiation is passed over thesurface of the monolith, parallel to each column, to a detector situatedat the end of the column. The composition of the stream leaving thepores in that column is estimated by processing the detector output,including Fourier transformation and/or weighted summation/differencingof the intensities at different wavelengths.

EXAMPLE 21

Pellets bearing catalytically-active groups capable of catalyzing theconversion of both the D- and L-stereoisomers of a reactant are treatedwith a variety of substances potentially capable of preferentiallysuppressing (temporarily or permanently) the conversion of theL-stereoisomer of that compound by that catalyst. The pellets aredistributed among the wells of a multiweli plate and exposed to amixture of the isomers of the compound to be modified. Pellets treatedwith the suppressor giving the greatest reduction in the activity forconversion of the L-isomer are useful in stereoselective modification ofthe D-isomer.

EXAMPLE 22

A ceramic monolith having channels arranged in perpendicular row/columnformat passing through its entire thickness is washcoated with porousalumina particles and the channels treated with catalyst precursors,which are activated. A potentially-reactive stream is flowed through thechannels of the monolith. A manifold consisting of an array of tubes,each smaller than the dimensions of an individual channel, is used tointroduce a stream containing ozone into the stream flowing through eachchannel, near its outlet. Reaction of the introduced ozone with thedesired product liberates light, which is detected by a camera directedat the monolith. The catalyst composition giving the strongest lightoutput is a useful catalyst for conversion of the reactants to theozone-reactive desired product.

EXAMPLE 23

A ceramic monolith having channels arranged in perpendicular sorow/column format passing through its entire thickness is washcoatedwith porous alumina particles and the channels treated with catalystprecursors, which are activated and then exposed to a potentiallydeactivating substance. A potentially-reactive stream is flowed throughthe channels of the monolith. A manifold consisting of an array oftubes, each smaller than the dimensions of an individual channel 71 isused to sample the stream flowing within each channel. Samples from eachchannel in turn are introduced into a gas chromatograph-massspectrometer combination through an arrangement of switching valves, andcatalyst compositions giving the highest yield of desired products areuseful in conversion of that reactive stream.

Modifications

Specific compositions, methods, or embodiments discussed are intended tobe only illustrative of the invention disclosed by this specification.Variations on these compositions, methods, or embodiments are readilyapparent to a person of skill in the art based upon the teachings ofthis specification and are therefore intended to be included as part ofthe inventions disclosed herein. For example, statistically-designedexperiments, and automated, iterative experimental process methods canbe employed to obtain further reductions in time for testing.Attachment/arraying of preformed catalytic elements (especiallyprecipitates, also single molecules and complexes such as metallocenes)onto a support, preferably by precipitating or deposition is useful inmany cases.

Detection can involve addition of some reagent to the stream leavingeach candidate, the reagent allowing detection of a catalyst productthrough staining or reaction to give a detectable product, light, etc.

The supports can comprise arrays with special arrangements for e.g., aheader of multiple delivery tubes for uniform flow distribution,inserted into each channel in a block.

The detection means can comprise electrochemical means, or a gammacamera for metals accumulation measurement, imaging elemental analysisby neutron activation and imaging by film or storage plate of emittedradioactivity, temperature measurement by acoustic pyrometry, bolometry,electrochemical detection. conductivity detection, liquid phase assay,preferably dissolving the support pellet and directly analyzing themetal loading; measuring refractive index in the liquid phase; observingthe IR emissions of product gases directly, without the usual source andusing instead the radiation hot gases emit at characteristicwavelengths.

Other modifications can include testing for selectivity afterdeliberately poisoning some sites, especially in chiral catalysis, etc.The formulations can be supported in the form of spots or layers on thesurface of a support containing wells or channels or channels extendingacross the entire extent of the support. The support can comprise a formof carbon, zeolite and/or plastic. The plastic can comprise a reactant.The support can hold a form of catalyst made by coprecipitation, oraluminum, or particles.

At least one of the formulations can preferably comprise a materialselected from the group consisting of transition metals, platinum, iron,rhodium manganese, metallocenes, zinc, copper, potassium chloride,calcium, zinc, molybdenum, silver, tungsten, cobalt and mixtures of theforegoing.

The label can comprise different isotopes or different mixtures ofisotopes.

The reaction conditions can comprise a pressure greater than one barabsolute pressure and the contact can be at a temperature greater than100 degrees centigrade

The method can comprise detection of temperature changes in the vicinityof a respective formulation due to reaction endotherm or exotherm.

The method can comprise treatment with a reducing agent.

The contacting step can be carried out in the presence of compoundswhich modify the distribution of the metal within the porous support.

The candidate catalyst formulations can be contacted in the form ofspots or layers on the surface of a support containing a washcoatsupported by an underlayer.

The stabilizing step can be carried out with a temperature gradient orother means whereby certain candidate catalyst formulations are exposedto different temperatures. The stabilizing can comprise calcining,steaming, drying, reaction, ion exchange and/or precipitation.

The detection of temperature changes due to reaction can employ acorrection for emissivity variations associated with differences inchemical composition.

The array of formulations to be tested can comprise preformedmetallocenes or other catalytic complexes fixed to a support.

The infrared radiation can be detected through the use of nondispersiveinfrared spectroscopy, or infrared-sensitive photographic film. Thedetector means can comprise means for physically scanning over an arrayof candidate formulations.

Observations at multiple wavelengths can be processed by mathematicalmanipulation e.g. transformation, weighted summation and/or subtraction,etc.

Reaction activity, reactants, or products can be detected through theuse of an added reaction which signals the presence of reaction orparticular compounds or classes of compounds.

Chemiluminescence can be used as an indicator of reaction activity, orparticular compounds or classes of compounds.

A substantially collimated radiation source can be employed in productdetection/imaging.

Multi-tube sampling can be used to lead into a mass spectrometer,chromatograph, or optical monitor.

To simulate aging, etc., the formulations can exposed to a deleteriousagent which reduces the activity of at least one formulation by at least10%, and then optionally exposed to steam, heat, H2, air, liquid wateror other different substance(s) or condition(s) which increase theactivity of at least one member of the collection by at least 10% overits previously-reduced activity whereby regenerability,reactivatability, decoking, or other catalyst property is measured. Thedeleterious agent can comprise elevated temperature, V, Pb, Ni, As, Sb,Sn, Hg, Fe, S or other metals, H2S, chlorine, oxygen, Cl, and/or carbonmonoxide.

Reference to documents made in the specification is intended to resultin such patents or literature being expressly incorporated herein byreference.

What is claimed is:
 1. A method for evaluating a plurality of candidatecatalysts, the method comprising simultaneously contacting a pluralityof candidate catalysts having differing compositions with one or morereactants under reaction conditions to catalyze at least one reaction,the plurality of candidate catalysts being simultaneously contacted withthe one or more reactants in a common reactor, and detecting reactionproducts or unreacted reactants using mass spectrometry to determine therelative efficacy of the plurality of candidate catalysts.
 2. The methodof claim 1 wherein the plurality of candidate catalysts aresimultaneously contacted with the one or more reactants in a parallelreactor comprising a plurality of reaction channels, each of theplurality of candidate catalysts being in its own reaction channel. 3.The method of claim 2 wherein the parallel reactor comprises a pluralityof reaction channels in a monolithic support.
 4. The method of claim 2wherein the parallel reactor is a flow reactor and the one or morereactants flow through each of the plurality of reaction channels. 5.The method of claim 1 wherein at least one reaction is catalyzed by eachof the plurality of candidate catalysts.
 6. The method of claim 1wherein the plurality of candidate catalysts are contacted with the oneor more reactants under reaction conditions that include a temperaturegreater than 100° C., and additionally, or alternatively, a pressure ofgreater than 1 bar.
 7. The method of claim 1 wherein the reactionproducts or unreacted reactants corresponding to the reaction catalyzedby each of the plurality of candidate catalysts are simultaneouslydetected using a corresponding plurality of mass spectrometers todetermine the relative efficacy of the plurality of candidate catalysts.8. The method of claim 1 wherein the reaction products or unreactedreactants corresponding to the reaction catalyzed by each of theplurality of candidate catalysts are simultaneously detected bymultistreaming or sampling into a corresponding plurality of massspectrometers to determine the relative efficacy of the plurality ofcandidate catalysts.
 9. A method for evaluating a plurality of candidatecatalysts, the method comprising flowing a reactant-containing streamthrough each of a plurality of reaction channels in a flow reactor, eachof the plurality of reaction channels comprising an inlet for receivinga reactant-containing stream, an outlet for discharging aproduct-containing stream, and a plurality of catalyst-candidates havingdiffering compositions, each of the plurality of catalyst candidatesbeing in its own reaction channel, such that the plurality of candidatecatalysts are simultaneously contacted with one or more reactants underreaction conditions and at least one reaction is catalyzed by each ofthe plurality of candidate catalysts, and detecting reaction products orunreacted reactants in the plurality of product-containing streams usingmass spectrometry to determine the relative efficacy of the plurality ofcandidate catalysts, wherein the flow reactor further comprises aplurality of sampling tubes adapted to provide fluid communicationbetween the plurality of reaction channels and a plurality of massspectrometers for multistream detection of a reaction product orunreacted reactant in each of the plurality of dischargedproduct-containing streams.
 10. The method of claim 9 wherein thereaction products or unreacted reactants in the plurality ofproduct-containing streams are simultaneously detected using massspectrometry.
 11. The method of claim 9 wherein the reaction conditionsinclude a temperature greater than 100° C., and additionally, oralternatively, a pressure of greater than 1 bar.
 12. The method of claim9 wherein the flow reactor comprises the plurality of reaction channelsin a monolithic support.
 13. The method of claim 9 wherein the pluralityof reaction channels are arranged in an array with a density of at least9 reaction channels per square inch.
 14. The method of claim 9 whereinthe flow reactor comprises the plurality of reaction channels arrangedin an array in a monolithic support with a density of at least 9reaction channels per square inch.
 15. The method of claim 9 wherein thereactor comprises twenty-four reaction channels and twenty-four catalystcandidates having differing compositions, each of the twenty-fourcatalyst compositions being in its own reaction channel.
 16. The methodof claim 9 wherein the flow reactor is adapted to provide uniform flowof the reactant-containing stream through each of the plurality ofreaction channels.
 17. The method of claim 9 further comprisingdepositing a plurality of catalyst precursors to the plurality ofreaction channels, each of the plurality of catalyst precursors being inits own reaction channel, and drying, and additionally, oralternatively, calcining the catalyst precursors to form the catalystcandidates.
 18. A method for evaluating a plurality of candidatecatalysts, the method comprising simultaneously contacting a pluralityof candidate catalysts having differing compositions with one or morereactants in a plurality of reaction wells in a batch reactor underreaction conditions such that at least one reaction is catalyzed by eachof the plurality of candidate catalysts, each of the plurality ofcatalyst candidates being in its own reaction well, sampling thereaction product mixtures in each of the plurality of reaction wells,and detecting reaction products or unreacted reactants in the sampledreaction product mixtures using mass spectroscopy to determine therelative efficacy of the plurality of candidate catalysts.
 19. Themethod of claim 18 wherein the reaction products or unreacted reactantsin the plurality of product-containing streams are simultaneouslysampled and simultaneously detected using mass spectrometry.
 20. Themethod of claim 18 wherein the reaction conditions include a temperaturegreater than 100° C., and additionally, or alternatively, a pressure ofgreater than 1 bar.
 21. The method of claim 1, 9 or 18 wherein theplurality of catalyst candidates are chemical conversion catalysts. 22.The method of claim 1, 9 or 18 wherein the plurality of catalystcandidates are hydrocarbon conversion catalysts.
 23. The method of claim1, 9 or 18 wherein the plurality of catalyst candidates are inorganiccatalysts.
 24. The method of claim 1, 9 or 18 wherein the plurality ofcatalyst candidates are zeolites.
 25. The method of claim 1, 9 or 18wherein the plurality of catalyst candidates are metallocenes.
 26. Themethod of claim 1, 9 or 18 wherein the plurality of catalyst candidatesare supported catalysts.
 27. The method of claim 1, 9 or 18 wherein theone or more reactants are in the gas phase.
 28. The method of claim 1, 9or 18 wherein the one or more reactants are in the liquid phase.
 29. Themethod of claim 1, 8 or 18 wherein the plurality of candidate catalystscomprises twenty-four candidate catalysts.
 30. The method of claim 1, 9or 18 wherein the plurality of candidate catalysts are formed bycalcining catalyst precursors at different temperatures.
 31. The methodof claim 1 or 18 wherein the plurality of catalyst candidates are metalsor metal oxides.
 32. The method of claim 1 or 18 wherein the pluralityof catalyst candidates are transition metals or transition metal oxides.33. The method of claim 1 or 18 wherein the plurality of candidatecatalysts comprises fifteen candidate catalysts.
 34. The method of claim1 or 18 wherein the reactor is a parallel batch stirred autoclavereactor.
 35. The method of claim 1 or 18 wherein the reactor is aparallel batch reactor comprising a plurality of agitated containers.36. A method for evaluating a plurality of candidate catalysts, themethod comprising flowing a reactant-containing stream through each ofat least twenty four reaction channels in a parallel flow reactor, eachof the at least twenty four reaction channels comprising an inlet forreceiving a reactant-containing stream, an outlet for discharging aproduct-containing stream, and at least twenty four catalyst candidateshaving differing compositions, each of the at least twenty four catalystcandidates being a metal or a metal oxide in its own reaction channel,the parallel flow reactor being adapted to provide uniform flow of thereactant-containing stream through each of the at least twenty fourreaction channels, such that the at least twenty four candidatecatalysts are simultaneously contacted with one or more reactants underreaction conditions and at least one reaction is catalyzed by each ofthe at least twenty four candidate catalysts, the reaction conditionsincluding a temperature greater than 100° C., and additionally, oralternatively, a pressure of greater than 1 bar, discharging theproduct-containing stream from each of the at least twenty four reactionchannels sampling the product-containing streams of each of theplurality of reaction channels through an array of tubes, the array oftubes comprising a plurality of sampling tubes in fluid communicationwith a plurality of mass spectrometers, and detecting the dischargedreaction products or unreacted reactants in the at least twenty fourproduct-containing streams using the plurality of mass spectrometers todetermine the relative efficacy of the plurality of candidate catalysts.